"Virgin Media’s Marketing Team" for sure, because it's their responsibility to test if their message works. There always will be some buggy software around. It

"Virgin Media’s Marketing Team" for sure, because it's their responsibility to test if their message works. There always will be some buggy software around. It could be feature phone, iOS, Windows Phone (devices are still alive), some tablet with SIM or whatever. It is "Marketing Team"'s responsibility to test if their message can actually reach their customers. Everything should be tested. Always.